Teach me about ITR 325's

[mlytle]

i'd run one, i think.

before i did it i would want to find out just how long one can expect to go before the subframe mounts need to be cut out and new pieces welded in. i'd want to know what that costs, and how hard the necessary parts (OEM factory installed!!!!) are to come by. if it's reasonable, i would then move on to finding the weight/power balance i thought was best for ITR.

they don't all do this. what drives the subframe failure is not replacing bushings when they wear out. the stock bushings are rubber. when they get old they loosen up and allow the subframe to move a little. this movement gradually flexes the mounting studs at the passeger side front first. the constant flexing causes the metal in the chasisis around the stud to fail. if you get a car that shows no signs of failure and put solid/urethane bushings in, you are good to go. if the flex has started, repair is needed. the repair is the installation of the factory plates that weld on around where the mounting studs/bolts go into the chassis. the plates are readily available at any dealer or place like bimmerworld. they are cheap too, like $20. the cost comes in labor to drop the subframe and weld the plates on, if you don't do this yourself. it really isn't that hard. nor is it necessarily required.

[JoshS]

if the flex has started, repair is needed. the repair is the installation of the factory plates that weld on around where the mounting studs/bolts go into the chassis. the plates are readily available at any dealer or place like bimmerworld. they are cheap too, like $20. the cost comes in labor to drop the subframe and weld the plates on, if you don't do this yourself. it really isn't that hard. nor is it necessarily required.

Marshall, I'm genuinely curious -- what document makes this repair legal on an IT 325i?

FYI, the Z3s have a different rear suspension design altogether, but have a very similar failure. When the bushings get worn, the rear subframe moves around a lot and can basically destroy the trunk floor. It's really ugly, much uglier than the E36 failures, when it happens. However, unlike with the 3-series, there is no reinforcement available from another BMW model. There is reinforcement available in the aftermarket ... of course, that reinforcement would be totally illegal in IT.

[mlytle]

Marshall, I'm genuinely curious -- what document makes this repair legal on an IT 325i?

FYI, the Z3s have a different rear suspension design altogether, but have a very similar failure. When the bushings get worn, the rear subframe moves around a lot and can basically destroy the trunk floor. It's really ugly, much uglier than the E36 failures, when it happens. However, unlike with the 3-series, there is no reinforcement available from another BMW model. There is reinforcement available in the aftermarket ... of course, that reinforcement would be totally illegal in IT.

the 325 reinforcement is not "from another model" it is for repair of the non-m3 e36's. the m3's came from the factory with reinforcement standard..they don't need it, nor can they use it.

yep, the z3's got the suspension from the e30's. rips in a difficult place. e36's rip in a place that is easily fixable with a plate.

i gotta stop here...this is a really dead horse being kicked.

[JoshS]

the 325 reinforcement is not "from another model" it is for repair of the non-m3 e36's. the m3's came from the factory with reinforcement standard..they don't need it, nor can they use it.

I hear people saying this a lot, but I'm asking ... why does everyone believe it? Seems like it's become common knowledge with no official basis. What BMW document says that what those parts are for?

And if you do a parts search for those part numbers, they come up as M3 parts (and not any other E36).

[robits325is]

BMW starting installing these plates in 1994 with the production of the M3. The plates came standard on all M3s and also standard from the factory on the famed 1994 M Technic 325is.

[JeffYoung]

Josh's question remains a good one.

1. Where is the factory TSB authorizing the installation of these plates on an E36 325is?

2. Is there any evidence they came on an E36 325is from the factory?

If neither, then I don't see how the plates are legal.

[DBurke]

To the OP the E36 is likely one of the most fun cars that someone could possibly put together. All the homework is done, it will fit all the tire that you want and there are suspension options out there galore. You can even pick up almost everything you need, right now to have a car as fast as you need it to be to win the ARRC in the bimmerforums classifieds at nearly 50% off. Things that aren't there are front brake pads and tires.

The chassis reinforcements are these: http://www.turnermotorsport.com/html..._ID=4111225649

If I had a week I could likely find the Roundel from over 10 years ago that had a statement regarding this from BMW.

I have no dog in this hunt. I am a BMW guy but when I was ready to buy the ex KVS ITS 325 all the weight/restrictor/dyno unrest was happening so I went another direction.

If I were to consider a car for ITR I would not consider any option other than the BMWs. No need to make life that difficult to go slower.

[Andy Bettencourt]

and also standard from the factory on the famed 1994 M Technic 325is.

Which would actually be a good reason to specifically disallow this car. As it turns out, they are NOT the same as the 325's.

But in the end - who really cares? As long as the owners are 'replacing' per factory specs and not 'reinforcing' per an upgrade, it's no big deal. Each car needs to be policed on it's own merits.

[robits325is]

Which would actually be a good reason to specifically disallow this car. As it turns out, they are NOT the same as the 325's.

But in the end - who really cares? As long as the owners are 'replacing' per factory specs and not 'reinforcing' per an upgrade, it's no big deal. Each car needs to be policed on it's own merits.

Agreed, but following the same logic would the RX-7 get twin piston calipers, trick 5th gear, rear wing and power steering delete? After all, those cars are about a second a lap faster than any other car in ITS.